Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Welcome to JUST ANSWER small engines, let me try to help you !! I don't know it all, but maybe together we can get you a satisfactory answer!
You can't start engine from key. So there is a safety switch likely keeping the circuit from being compete. Usually on zero turn there are two arm switches, on on each arm, that has to be in the neutral position before starter will work. Check each arm switch for being stuck. Use some WD40 on both switches and work the arms to free up. See if that will help
It will be safety switch, seat, or arm switch or harness to them.
I see question is still open, did you find probelm?